Learn to use the code editor with C#

In this 10-minute introduction to the code editor in Visual Studio, we'll add code to a file to look at some of the ways that Visual Studio makes writing, navigating, and understanding C# code easier.

If you haven't already installed Visual Studio, go to the Visual Studio downloads page to install it for free.

This article assumes you're already familiar with C#. If you aren't, we suggest you look at a tutorial such as Get started with C# and ASP.NET Core in Visual Studio first.

Tip

To follow along with this article, make sure you have the C# settings selected for Visual Studio. For information about selecting settings for the integrated development environment (IDE), see Select environment settings.

Create a new code file

Start by creating a new file and adding some code to it.

1. Open Visual Studio. Press Esc, or choose Continue without code on the start window, to open the development environment.

2. From the File menu on the menu bar, choose New > File, or press Ctrl+N.

3. In the New File dialog box, under the General category, choose Visual C# Class, and then choose Open.

   A new file opens in the editor with the skeleton of a C# class. You don't have to create a full Visual Studio project to gain some of the benefits that the code editor offers—all you need is a code file.

   

Use code snippets

Visual Studio provides useful code snippets that you can use to quickly and easily generate commonly used code blocks. Code snippets are available for different programming languages including C#, Visual Basic, and C++.

Let's add the C# void Main snippet to our file.

1. Place your cursor just above the final closing brace } in the file, and type the characters svm. svm stands for static void Main—don't worry if you don't know what that means yet.

   A pop-up dialog box appears with information about the svm code snippet.

   

2. Press Tab twice to insert the code snippet.

   You'll see the static void Main() method signature get added to the file. The Main() method is the entry point for C# applications.

Available code snippets vary for different programming languages. You can look at the available code snippets for your language by choosing Edit > IntelliSense > Insert Snippet or pressing Ctrl+K, Ctrl+X, and then choosing the folder for your programming language. For C#, the snippet list looks like this:

The list includes snippets for creating a class, a constructor, a for loop, an if or switch statement, and more.

Comment out code

The toolbar, which is the row of buttons under the menu bar in Visual Studio, helps make you more productive as you code. For example, you can toggle IntelliSense completion mode, increase or decrease a line indent, or comment out code that you don't want to compile.

Let's comment out some code.

1. Paste the following code into the Main() method body.

   // someWords is a string array.
   string[] someWords = {
       "the",
       "quick",
       "brown",
       "fox",
       "jumps"
   };
   
   string[] moreWords = {
       "over",
       "the",
       "lazy",
       "dog"
   };
   
   // Alphabetically sort the words.
   IEnumerable<string> query = from word in someWords
                               orderby word
                               select word;
   

2. We're not using the moreWords variable, but we might use it later so we don't want to delete it. Instead, we'll comment out those lines. Select the entire definition of moreWords down to the closing semicolon, and then choose the Comment out the selected lines button on the toolbar. If you prefer to use the keyboard, press Ctrl+E, Ctrl+C.

   

   The C# comment characters // are added to the beginning of each selected line to comment out the code.

Collapse code blocks

We don't want to see the empty constructor that was generated for Class1, so to unclutter our view of the code, let's collapse it. Choose the small gray box with the minus sign inside it in the margin of the first line of the constructor. Or, if you prefer to use the keyboard, place the cursor anywhere in the constructor code and press Ctrl+M, Ctrl+M.

The code block collapses to just the first line, followed by an ellipsis (...). To expand the code block again, select the same gray box that now has a plus sign in it, or press Ctrl+M, Ctrl+M again. This feature is called Outlining and is especially useful when you're collapsing long methods or entire classes.

View symbol definitions

The Visual Studio editor makes it easy to inspect the definition of a type, method, or variable. One way is to go to the definition, in whichever file has it, by choosing Go to Definition or pressing F12 anywhere a symbol is referenced. An even quicker way that doesn't move your focus away from the code you're working on is to use Peek Definition.

Let's peek at the definition of the string type.

1. Right-click on any occurrence of string and choose Peek Definition from the content menu. Or, press Alt+F12.

   A pop-up window appears with the definition of the String class. You can scroll within the pop-up window, or even peek at the definition of another type from the peeked code.

   

2. Close the peek definition window by choosing the small box with an "x" at the top right of the pop-up window.

Use IntelliSense to complete words

IntelliSense is an invaluable resource when you're coding. It can show you information about available members of a type, or parameter details for different overloads of a method. You can also use IntelliSense to complete a word after you type enough characters to disambiguate it.

Let's add a line of code to print out the ordered strings to the console window, which is the standard place for output from the program to go.

1. Below the query variable, start typing the following code:

   foreach (string str in qu
   

   You'll see an IntelliSense pop-up appear with information about the query symbol.

   

2. To insert the rest of the word query by using IntelliSense word completion, press Tab.

3. Finish off the code block to look like the following code. You can practice further with code snippets by entering cw and then pressing Tab twice to generate the Console.WriteLine statement.

   foreach (string str in query)
   {
      Console.WriteLine(str);
   }
   

Refactor a name

Nobody gets code right the first time, and one of the things you might have to change is the name of a variable or method. Let's try out Visual Studio's refactor functionality to rename the someWords variable to unsortedWords.

1. Place your cursor over the definition of the someWords variable, and choose Rename from the right-click or context menu, or press F2.

   A Rename dialog box appears at the top right of the editor.

   

2. Enter the desired name unsortedWords. You'll see that the reference to unsortedWords in the query assignment statement is also automatically renamed. Before you press Enter, select the Include comments checkbox in the Rename pop-up box.

   

3. Press Enter, or choose Apply in the Rename dialog box.

   Both occurrences of someWords in your code have been renamed, as well as the text someWords in your code comment.

Next steps

Learn about projects and solutions

See also

• Code snippets
• Navigate code
• Outlining
• Go To Definition and Peek Definition
• Refactoring
• Use IntelliSense